Small Things

Overview

This exercise builds on the previous exercises in Activity 2 Observation and measurement. It provides students with experience in sorting out objects of different sizes. 

The emphasis is on researching objects at the macro, micro and nano levels. It may be useful to discuss the following table with your students before attempting this exercise.

What you need

• The set of cards of 16 objects of different sizes. The cards are made by using Activity sheet 3.1 Image list
• Access to the internet

The approach

A. What size?

This is a group activity. The set of cards are of different objects at the macro, micro or nano scale. Distribute the cards to your students. On each card is a picture of an object and its name.

• The size of these objects varies a great deal. Some of these images need to be measured in metres, while others need to be measured in millimetres, micrometres or nanometres.
• The first task for the class is to order the images from largest to smallest.
• Encourage your students to discuss the images, what they might be and their possible size.
• Students are then to organise and order the images in size from largest to smallest.
• This is a ‘first cut’; students may not know too much about their object and there may be a deal of uncertainty and disagreement.
• Record their final order. If students can’t agree, get them to record their order.
• Ask them to estimate the size of the object (this will be rough, in metres, cm, mm, µm, nm)

It is a great opportunity for you to listen to the students discussing the images and identify misconceptions and understandings.

B. Finding out about your object

• Distribute Activity sheet 3.1
• The task of the student groups is to find out as much as they can about the object they have been given. What is its size? What does it do? Do we use it? Does it affect us? What equipment do we need to see it?
• Present to the class what students found.

C. What size revisited?

Revisit the order of size completed in part A. Ask the students to create a new order given the information they have obtained. Get them to discuss any differences.

This is a great opportunity to highlight the nano objects, particularly DNA.

Extension

Students can research and find out about the instruments used to ‘see’ the images at the macro, micro and nano levels.

Seel Also

• The Strange World of Small Things
• Stereo Microscopes