Assessment Ideas

When students interact with simulations, they are engaged in a very different type of learning that when they are reading. The goal of the PSI Sim™ designers was to promote the development of deeper, more personal ways of thinking about science. To help address the differences between rote memorization and interactive, inquiry-based methods for assessment purposes, we believe it is necessary to go beyond typical questioning strategies used in most text books. That is, different types of learning require different types of assessment. Of course, assessment must relate directly to program goals and course objectives.

You may find it convenient to use the PSI Sims™ themselves as part of assessment. For example, the teacher might set up a scenario in the PSI Sim™ and print it out along with a "What-if" or "What will happen now" question. Be warned that non-traditional questioning strategies need to be introduced carefully so that students "learn" that you expect them to think differently about their responses. It is wise to try out new assessment strategies with self-assessments before using them for grading purposes.

Let's consider some basic examples of alternate assessment strategies. In a rote learning assessment, a student might be asked to state a definition of "electrolyte". Another method of assessment might be to "give an example of an electrolyte and an example of a non-electrolyte." Perhaps the students might "draw a diagram of an electrolyte being used in a practical way." Another example might be, "what problems might arise in an experimental situation if a non-electrolyte were replaced with the electrolyte by accident." PSI Sims™ sometimes include real-time graphing components. In these cases, students might be asked to make connections between reading a meter and reading a graph. When should one be used rather than the other? PSI Sims™ often allow the student to manipulate more than one variable. Questions can be asked to see how the student would anticipate the result of modifying the two variables in certain ways, noting the relationship between the variables. The advantage of the PSI Sim™ in this case is that it offers a concrete, interactive example of the model.

Below we present concrete examples of a few types of assessment that you may find useful when using PSI Sims™.

Case Assessment

In The Adventure of the Dancing Men, Sherlock Holmes had to decipher a set of codes that translated to an English phrase. Each code looked like this:

To solve the case, and crack the code, Holmes had to use more than what was in the images, he had to use his knowledge of the English language, and how it worked. Can you come up with any ideas about the method Holmes used to crack the code? Write a paragraph discussing your ideas.

Discussion: The first step in breaking any cipher is to try to find features which correspond to the original plain text. Whereas codes substitute groups of letters or figures for words, phrases or even complete concepts, ciphers replace every individual letter of every word. They therefore tend to reflect the characteristics of the language of the original text. This makes them vulnerable to studies of letter frequency; for example, the most common letters in English are E, T, A, O, and N. If a reasonable amount, or 'depth,' of English text enciphered in the same simple cipher were studied for "letter frequency," the letter that came up most often would represent E. The second most common letter would be T and so on. By working this out and filling in the letters, some will form obvious words with letters missing, allowing the code breaker to fill in the gaps and recover those letters as well. (excerpt from Nova Online: Mind of a Codebreaker)

Comprehensive Achievement Test

A simple code can be created by reversing the alphabet. Like this:

ABCDEFGHIJKLMNOPQRSTUVWXYZ
ZYXWVUTSRQPONMLKJIHGFEDCBA

What does the message: Smd ziv bmf gmwzb mean?

(A) How are you doing? (B) How does your garden grow? (C) How are you today? (D) Why are you crying?

Informal Assessment

Postal bar codes are made up of groups of five bars with three short and two long bars. A specific number is assigned to each bar position. The first bar is assigned the value of 7, the second bar 4, the third 2, the fourth 1, and the last bar is 0. Figure 1 below shows the numbers assigned to each bar. A short bar indicates do nothing with this value, a long bar indicates to sum the values. Figure 2 shows an example code and solution. Which digit is represented by the bar code appearing in Figure 3?

Traditional Assessment: Multiple Choice Test

A multiple choice test that can be used as a post-test for The Codebreaker Experiment is available by clicking here:

Codebreaker Post-Test

Project Based Assessment

Using the Morse Code chart below, create a message on paper using dots and dashes. Ask a friend to see if he or she can decode the message by listening to it, writing it down, and decoding it. You can use a pencil to tap out the code, or use a cell phone to make long and short tones using a single key (just don't press the call button!). If you enjoy using Morse Code, you can create a Morse Code Buzzer. You will find instructions on this website: http://terrax.org/comm/morsecode/buzzer.aspx. Ask your teacher about building a science project around the buzzer.